Y-flanged containers and cover members therefor

ABSTRACT

A closing cover member is provided for the mouth opening of an open-ended vessel such as a pail having a rim and made of a structural plastic material having nonrigid, flexibly distortable mechanical properties, such as high-density polyethylene, the pail having a peripheral rigidifying flange rising outwardly from the exterior of the sidewall commencing uniformly below the rim and forming an acute angle with the sidewall, the outer margin of the rigidifying flange terminating in a peripheral upwardly inturned short hook flange, and the cover member having a depending marginal flange wall terminating in a conic outwardly rising peripheral flange adapted to be forcibly nested upon the rigidifying flange with the edge engaged continuously under the hook flange, whereby axial pressure within the pail tends to enhance the sealing pressure along the contact areas of the outer and inner edges of the conic flange; either the conic flange or the rigidifying flange may be rigid, i.e. made of metal, if the other is polyethylene; where resistance to internal pressure is not required, roll-edge cover members may be snapped-on under the hook flange.

2,767,754 10/1956 Lederer 150/0.5 2/1957 Tupper ISO/0.5 2,828,789 4/1958Groendyk ISO/0.5

b so

O United States Patent [1113,566,946

[72] Inventor James Ian Mac Donald 2,914,104 1 H1959 Jocelyn ISO/0.5 7087th Ave.S.W., Calgary, Alberta, 3,1 17,691 1/1964 Williams. 150/0.5XCanada 3,307,603 3/1967 Swett 150/0.5 E 3:??? 1968 PrimaryExaminer-George E. Lowrance Patented Mar. 2, 1971 Attorney Roman] F1lpkOWSkl [32] Priority Aug. 9, 1 968 V [33 1 a Canada ABSTRACT: Aclosing cover member is provided for the 7 6 [31] 02 mouth opening of anopen-ended vessel such as a pail having a rim and made of a structuralplastic material having nonrigid, I 54] FLANGE CONTAINERS AND COVERflexibly distortable mechanical properties, such as high-densitypolyethylene, the par] having a peripheral ngrdifylng flange MEMBERSTHEREFOR rising outwardly from the exterior of the sidewall commenclng13 Claims, 9 Drawing Figs.

uniformly below the rim and forming an. acute angle with the U.S. Cl.sidewall the outer margin of the flange terminating 220/60, 220/74 in aperipheral upwardly inturned short hook flange, and the [51] Int. Cl...B65d 11/06, cover m mber having 3 depending marginal flange wall te365d 1 1/26, 365d 43/10 minating in a conic outwardly rising peripheralflange adapted [50] Field of Search ISO/0.5; to b f ibl nested n therigidifying flange with the edge 220/60,; 215/1'5 engaged continuouslyunder the hook flange, whereby axial pressure within the pail tends toenhance the sealing pressure [56] References cued along the contactareas of the outer and inner edges of the UNITED STATES PATENTS conicflange; either the conic flange or the rigidifying flange may be rigid,i.e. madeof metal, if the other is polyethylene; where resistance tointernal pressure is not required, roll-edge cover members may besnapped-on under the hook flange.

PATENTEU MAR 21% 3,566,946

Thisinvention relates to open-ended containers provided with sealingcovers having utility for the storage and transportation of liquidmaterials generally and foodstuffs specifically, and the invention ismore particularly embodied in an improved scalable pail provided with arim and a planar cover releasably seated upon therim, the pail having aperipheral made of a nonrigid, flexibly distortable materialsuch ashigh"density linear polyethylene and provided with a planar cover member ofthe same or similar material, or even ofa relatively rigid material suchas metal, strongly resist internal pressures and fluid surges,permitting stacking andshipping of such containers without risk of lossof seal ortren oval of the cover under usual handling conditions, yetmay be readily opened by manual stripping of the cover starting at anypart of its periphery. The reinforcement provided .by the rigidifyingflange maintains the shape of the container mouth opening excellently inhandling and pouring.

Heretofore the retention of a releasable planar cover member made of anonrigid flexibly distortable material fitted on the open end of acontainerhas dependedeither on axially engaging an inward bead edgecarried by adepending peripheral flange of the. cover to hook under anoutwardly ,extending bead or projection of the rim of the containeigoron pressing an annular groove defined by continuous sidewalls of anannularly raised peripheral portion. of the cover about the edges of theopen end. The sealing action in either arrangement depends on theadhesion of a radially distended peripheralportion of the cover to theexterior. surface of the end portion of the containers While the holdingeffect provided by such covers in smaller sizesof containers subjected.to gentle handlinghasproven adequate, the nature of the seal permitsany moderate increase in internal pressure or ;occurence of a fluidsurge to lift the cover, bausing leakage. Furthermore, any downwardmovement of the container in handling causing the exterior to strikean'obstacle may inadvertently strip the cover by applying lifting forcealong some part of its periphery. In addition, radial squeezing.,may sodistort the rim despite provision of an offset in the. containersidewall as tomake the seal ineffective along thedistorted sectorsunless the thickness of the parts is very considerably increased.

l have found that a novel and highly advantageous :locking seal may beprovided for an open-ended containerwherein the sealing action does notdepend on the adhesion of a distended annular portion of the cover, butrather on the radial compressive strength of a peripheral flangeportionof the cover which is seated into and is gripped between theexterior ofthe container and a hook flange joined with the outerend ofa rigidifyingannular conic flange rising outwardly from the container sidewall at anacute angle. This arrangement transfers the cooperate to increase;radial stiffness of the closed container,

itsresistance to deformation by lateral shocks is greatlyimnot occur.Finally, the provision of the integral rigidifying flange risingoutwardly below the mouth of the container at. an acute angle andterminating in a hook flange at about the level of the rim tends togreatly stiffen and] maintain the cross sec- ,tion of the open end infilling and pouring.

Essentially, therefore, the invention consists in providing, an open endcontainer formed as a hollow body having an enclosing sidewallterminating as a rim defining a mouth opening, a peripheral rigidifyingflange integral with the container sidewall and rising outwardly belowthe rim at an acute angle preferably about 45, the flange terminating ina continuous inturned hook flange disposed at about the level of therim, and a mating cover member having an intermediate planar portionconnecting with a continuous. rim-girdling depending flange forming ajunction at its lower end with the inward margin of a peripheral sealingflange extension of annular conic form, thesealing flange being of suchshape and inclination that its under surface may be axially nested uponthe upper surface of the rigidifying flange when the hook flange hasbeen forcibly flexed outwardly. by insertion of the cover margin toeffect a snap-on locking engagement undenthe hook flange,

the inner margin of the sealing flange being pressed tightly against thecontainer exterior to effect a fluidtight seal.

. In the construction of a container which may be a .pail by a moldingoperation according to the invention, using for example, high-densitylinear polyethylene, the core mold is provided with a slight taper inthe sidewall andthe exterior mold is provided with a break plane,intersecting the junction of the rigidifying flange with; the hookflangeuln molding the cover of polyethylene or similar flexiblydistortable material, the peripheral sealing flange is shaped to conformto the plan form of the rigidifying'fla nge and the rim-girdlingdepending flange is shaped to, closely engage the exterior ,of the rim,i.e., the plan form .will be generally either circular, or rectangularwith rounded cornersfThe cover member may also be constructed, accordingto one alternative, with the intermediate portion axially depressedbelow the level of the rim, by providing two depending flanges radiallyspaced and forming an inverted channel portion, defining an upwardgroove having an axial extent .such that the rim is seated in the groovebottom when the sealing flange is nested upon the rigidifying flange.

The container may alternatively be closed by using a relatively simplesheet member shaped as a disc or to the plan form of the container,,oras a planar member having a dependingperipheral sidewall carrying anoutward bead which may ,proved as compared with prior art forms..Sinceno part of the be engaged under the hook flange to effect covering; suchcover members however would provide less effective sealing, and theenhanced sealing described for the conically flanged cover members wouldnot be present. Such cover members may be used where the-fluidtightsealing action is not necessary andwhere handling is gentle.

It is entirely feasible'to construct the container of metal or otherrigid material having a cover molded of a flexibly distortable material,or ,vice versa, provided onlythat at least one of. the rigidifyingflange and the sealing flange have the required distortability when thecover is axially pressed down ntoengage its margininside the hookflange.

.of the pailcontents from the wide mouth opening;

BIG. 3 is anaxial diametral section in enlarged scale taken on line 3-3of FIG. 1 showing the engagement of thecover in closing relation on therim and locked with the rigidifying flange;

FIG. 4is a view similar to FIG. 3 showing the coveraxially separated at.the position of initially engaging the rim;

FIG. 5 is an analytic diagram relating to FIG. 3 illustratingsealingforce and lockingaction;

FIG. 6 is a section similar to FIG. 3 showing a cover modified toprovide an inverted rim-engaging channel;

FIG. 7 is a cross-sectional view showing a modified shorter rigidifyingflange disposed at a larger acute angle wherein the container is made ofmetal and the cover of polyethylene; and

FIGS. 8 and 9 show alternative cover members and rim heights employing adisc cover and a cap cover.

Referring to the drawing, a container or pail generally designated 10having a flat bottom wall 11 is formed with an upwardly extendingsidewall 12 shaped as a frustum of a cone, having a wall taper of a fewdegrees, the sidewall being formed with an offset portion 13 providingimproved radial wall rigidity. The upper end of the sidewall terminatesin a rim 14.

Below the rim 14 a continuous peripheral rigidifying flange 15 ofannular plan form extends integrally from the container sidewall at ajunction 16 therewith, rising at an acute angle designated D which mayrange from about 15 to about 75 with respect to the sidewall, apreferred angle as shown being about 45. The outer margin 17 of theflange 15 carries an upwardly inturned edge flange 18 having a bluntmarginal edge 19 and a conic annular surface 20 disposed to provide acon tained angle of 90 or slightly less than 90 with respect to theupper surface 21 of the rigidifying flange. The upper margin of the edgeflange is in a plane disposed close to theplane of the rim 14, orpreferably slightly below it The interior portion 22 of the containerbetween the rim l4 and the junction 16 is preferably formed with areduced taper and may be nearly vertical, or may be provided with asmall taper opposite to that of the interior of the sidewall 12, tofacilitate applying or removing the cover generally designated 23. Thecontainer is preferably molded of high-density linear polyethylene orother structural material which is similarly flexibly distortable, i.e.having a capacity of returning to its original shape after release of alimited deforming pressure. The cover 23 may be molded, as shown, of thesame or similar material, and is provided with an intermediate planarportion 24 which may be disclike, or slightly dished inwardly as shown.

A depending flange 25 defining the periphery of the inter mediateportion 24 is so dimensioned that the inner surface 26 may be axiallyforced into close engagement about the rim and sidewall portion 22. Thelower margin 27 of flange 25 is formed with a lateral nose or inwardcontinuous projection disposed at the same diametral distance from thecontainer axis as the surface 26, or preferably at a slightly lesserradius. The flange is integral with a peripheral sealing flange 28having conic annular form, the undersurface 29 of which is disposed atabout the same or a slightly greater angle than is the surface 21. Asshown in FIGS. 3 and 6, the angular relationship should be such thatpreferably the sealing flange seats in nested relation upon the uppersurface 21 of the rigidifying flange with a small clearance between theadjacent conic surfaces in the vicinity ofjunction 16.

The flange 28 has a length as measured along a radial element of thegenerating cone which is a multiple of the thickness of the flange, toprovide sufficient flexure to permit axial insertion under the flangesurface 20. The distance between the outermost marginal edge 30 of theflange 28, which is shaped to a rounded profile, and the inwardprojection 27, is made slightly larger than the greatest distancebetween the flange surface 20 and the exterior surface 22 so thatinsertion of flange 28 causes a slight distension outwardly of hookflange 18. It has been found that injection molding methods favor theinherent radial contraction of marginal edge 27 so that deliberateprovision in the making of the molds may be unnecessary to secure aninward protuberance. It is to be understood that compressive sealing maybe obtained even when the inner margin of flange 28 is flush with theinternal surface of flange 25.

As may best be seen from FIG. 4, the horizontal extent of flange 28between the marginal edge portions 27 and 30 is larger, by the distancea, than the minimum horizontal distance between the nose 19 of hookflange 18 and the exterior sidewall 22. Consequently, axial engagementof the cover will tend to inwardly distort the container rim 14 as edge27 slides down along the outer surface 22, and when edge 30 encountersthe nose 19 the flange 28 will tend to be flexed as edge 30 lifts due tointerference, along a sector being forced into locking engagement;flange 18 will be distended along such sector until edge 30 has seatedundersurface 20 in contact therewith.

In the seated position of cover 23 its sealing flange 28 will thereforebe under radial compressive stress while rigidifying flange 15 will beunder slight tensile stressxReferring to the stress diagram, FIG. 5, theeffect of internal pressure within the closed container is to apply avertical axial load, which exerts a force F along a unit sectorallength, transmitted by tension link 125 representing the dependingflange 25. Since the materials are flexibly distortable, the sectioncannot strictly be analyzed as though the structural elements werepin-jointed linkages; however, use of this method will at least serve toillustrate the locking and sealing actions enhanced by internalpressure.

The sectoral element 128 of the sealing flange may be taken as anend-loaded strut which is pivotally held at one end by a frame andbearing in free sliding relationship against vertical frame 122 at itsother end, which is pin connected to the end of tension link 125. Whenthe angle between the elements 125 and 128 is I the compressive load isF/Cos I the horizontal sealing pressure I-I against frame 122 is F.Tan 1and the tension load T in the structural member 115 acting along lineb-b is F/Cos I The total compressive load in the sealing flange, as wellas the sealing pressure, will be increased by the contribution due toflexing of flange 18 resulting from initial seating of the cover.

When I is 45, the horizontal sealing pressure H exerted between marginaledge 27 and the container sidewall will be substantially equal to theaxial load F carried by the flange 25. Since the area of contact alongedge 27 is relatively small, the unit sealing pressure developed betweencontiguous surfaces is greatly increased as compared with the unitinternal pressure which produces the axial load F. At the same time, theunit sealing pressure exerted between the edge 30 and the surface 20will be even higher, since at 45 the magnitude of F/Cos Q is about 1.4F.

The line of action of the compressive stress, designated z-z, will tendto make a slight angle with respect to the upper surface 21 as the edge27 is lifted slightly away from junction 16 due to distortions resultingfromthe axial load. The rigidifying flange will tend to elongateslightly and because of the finite distance x between the line z-z andthe medial tension line b-b in the rigidifying flange, a torque will beexerted tending to spread the flange 18. However, due to the favorablebeam strength of the latter even at moderate wall thicknesses,considerable internal pressure may be resisted without noticeabledistortion.

In general, the containers according to the invention will be used withinternal pressures not greatly different from atmospheric, andvariations therefrom within the container will in part be taken up byflexing of the intermediate portion 24, Fluid surges and upending offilled containers however will produce local internal pressuredifferences either above or below atmospheric, and the efficacy of sealenhancing in resisting loss of fluid under such disturbances isexcellent.

When filled containers are to be shipped in stacked grouping, thealternative cover member of FIG. 6 is preferred, wherein an additionalflange 32 extending upwardly is provided inwardly of flange 25, theflanges being joined by a rounded annular portion 33 overlying the rim14. Due to taper of the sidewall, the lower end will seat inwardly ofsidewall 32 upon shelf 34 formed at the junction of intermediate planarportion 24 with the flange 32. It will be evident that large axial loadsapplied tending to press annular portion 33 down on the rim will havelittle effect since sidewall 12 is radially stiffened and gains highresistance to buckling or crushing due to support by closely engagingflanges 25 and 32. Any increase in internal pressure resulting fromtheaxial load of stacked pails and contents acts on the annularundersurface of portion 33,

tending to lift this area and consequently enhancing the sealingpressure on edge 27.

When angle 1 is'made smaller, the, horizontal sealing pressure H and thesealing flangecompressive stress Care each diminished while use ofangles greater than 45 tends .to, increase both H and C and to bringthem to a more nearly equal higher value. When the container wallisrigid, as shown in- FIG. 7, an angle .(b which may be as large as 75is practically feasible when the compressive strength of the flange 28is made suitably large.

If the internal pressure of the container of FIG. 3 should fallconsiderably below atmospheric, the axial load F is reversed, and theundersurface 31 of the cover'will be compressed against rim l4. Radialinward distortion produced in the marthe cover member 23 is securelylockedand, sealed whether internal pressure is above or belowatmospheric. It is nevertheless easy to remove the coveronce anysectoral portionof edge 30 has been disengaged from under flange 18. To

facilitate stripping the cover from the mouth opening, an integral tabis provided as shown in FIG, 1, attached along a short arcuate length ofthe upper side of flange 28 adjacent edge 30. When the tab is graspedand pulled upwardly and inwardly until some part of edge 30 is exposedand a gap 36 is provided, adjoining sectoral portions of flange 28 maybe freed by axial pull on them, or by prying them free with a tool slidunder the surface 29. n

ln those use applicatio'ns-where-a cover member providing low resistanceto internal pressure may be substituted, a disc having a peripheral edge37 shown in FlG.'8 is shaped to the plan of the hook flange 18,, so thatedge 37 may be sectorally advanced in engagement under the'surface 20.The level of rim 14 is advantageously either slightly lower than surfaceor at nearly the same level so that the marginal zone may be flexedslightly and pressed upon rim 14. Where the rim l4 lies in a planeconsiderably above the plane of surface 20, the cap sidewall and a beador other outward continuous protuberance 38 shaped to snap under thenose 19 and spring outwardly against surface 20.

conic annular form integrally joined with said sidewall along a junctionspaced below said rim, rising outwardly at an acute angle, andterminating in an upwardly inturned annular hook flange, said hookflange having an inner margin spaced from said rim, said cover memberhaving a mouth-closing portion and a depending sidewall portion carryingan annular conic sealing flange adapted to be nested upon saidrigidifying flange when said cover member is forcibly affixed in closingrelation over-said mouth opening, said conic sealing flange having anouter margin adapted to be distortably received in locking engagementunder said hook flange and having an inner margin adapted to-sealinglyengage said sidewall of said container proximalto said junction and toexert increased sealing pressure on said sidewall in response to axialforce tending to lift said cover member.

2. A container and cover member as set forth in claim l wherein saidmouthclosing portion conformably contacts said rim when said covermember is affixed in closing relation.

3. A container and cover member as set forth in claim 1 wherein theinner margin of said annular conic sealing flange projects radiallyinwardly of said depending sidewall and forms a sealing protuberance.

cover of FIG. 9 is used, being provided with a depending It is to beunderstood that although the description has been directed toembodiments having tapering enclosing sidewalls terminating in a rimwhose diameter is the largest diameter of the body, it is entirelyfeasible to construct containers of constant cross-sectional dimensionsalong their axial length, i.e. to provide cover members which in effectform removable end walls for cylindrical bodies such as tubes or pipes.

lclaim: i

l. A container and a cover membertherefor formed of a flexiblydistortable structural material, said container comprising a hollow bodyhaving an'enclosing sidewall and a closing bottom wall, the upper end ofsaid sidewall terminating in a rim defining a mouth opening,arigidifying flange member of 4. A container and cover member as setforth in claim 1 wherein said inner margin of said hook flange lies in aplane spaced adjacently below theplane of said rim.

5. A container and cover member as set forth in claim 1 wherein theinner margin of said hook flange lies in a plane spaced slightly abovethe plane of said rirn.

' 6. A container and cover member as set forth in claim 3 wherein saidacute angle is between about 15 and about 75.

7. A container and cover member as set forth in claim 6 wherein saidacute angle is about 45.

8. A container and cover member as set forth in claim 6 .wherein saidhook flange, has an undersurface which is inclined to the upper surfaceof said rigidifying flange with an included angle which is a right angleor slightly less than a right angle.

9. A container and cover member as set forth in claim 2 wherein saidmouth closing portion of'said cover member comprises a central planarportion, an upwardly extending wall portion integrally joined with saidplanar portion, an annular rounded portion merging with said upwardlyextending wall portion and with said depending sidewall portion, saidannular rounded portion having an undersurface conformably i whereinsaid rim has the largest diameter of said hollow body.

13. A container and cover member therefor as set forth in claim 3wherein said hollow body hasconstant cross-sectional dimensions betweensaid junction and said rim.

2. A container and cover member as set forth in claim 1 wherein saidmouth closing portion conformably contacts said rim when said covermember is affixed in closing relation.
 3. A container and cover memberas set forth in claim 1 wherein the inner margin of said annular conicsealing flange projects radially inwardly of said depending sidewall andforms a sealing protuberance.
 4. A container and cover member as setforth in claim 1 wherein said inner margin of said hook flange lies in aplane spaced adjacently below the plane of said rim.
 5. A container andcover member as set forth in claim 1 wherein the inner margin of saidhook flange lies in a plane spaced slightly above the plane of said rim.6. A container and cover member as set forth in claim 3 wherein saidacute angle is between about 15* and about 75*.
 7. A container and covermember as set forth in claim 6 wherein said acute aNgle is about 45*. 8.A container and cover member as set forth in claim 6 wherein said hookflange has an undersurface which is inclined to the upper surface ofsaid rigidifying flange with an included angle which is a right angle orslightly less than a right angle.
 9. A container and cover member as setforth in claim 2 wherein said mouth closing portion of said cover membercomprises a central planar portion, an upwardly extending wall portionintegrally joined with said planar portion, an annular rounded portionmerging with said upwardly extending wall portion and with saiddepending sidewall portion, said annular rounded portion having anundersurface conformably contacting said rim when said conic sealingflange is seated with its outer margin locked under said hook flange.10. A container as set forth in claim 3 wherein said mouth opening iscircular.
 11. A container and cover member as set forth in claim 3wherein said mouth opening is rectangular in plan view having roundedcorners, and said rigidifying flange comprises straight strip sideportions merging with conic corner portions.
 12. A container and covermember as set forth in claim 3 wherein said rim has the largest diameterof said hollow body.
 13. A container and cover member therefor as setforth in claim 3 wherein said hollow body has constant cross-sectionaldimensions between said junction and said rim.